1. Field of the Invention
The present invention relates to a disc playing apparatus for playing an information recording disc (simply referred to as disc hereinafter) carrying a signal for controlling the operation of electronic musical instruments.
2. Description of Background Information
A standard called MIDI (Musical Instrument Digital Interface) has been developed so as to enable a music performance using a plurality of sound sources by combining a plurality of electronic musical instruments such as a music synthesizer or an electronic piano.
A term "MIDI apparatus" is used for designating an electronic musical instrument which includes a hardware according to MIDI standard and has a function to transmit and receive a data format signal (referred to as MIDI signal hereinafter) as a musical instrument control signal of a defined form carrying musical information.
As for the recording format used for recording information on a disc, a subcode carrying play control information or the like is recorded on a disc such as a CD (compact disc), CD-V (cd-video), LD (laser disc) with CD format digital sound. The subcode is constituted by channels P, Q, R, S, T, U, V, and W in which channels P and Q are used as the control signal of the disc player.
On the other hand, R through W channels are vacant channels designated as user's bit, and various types of utilization of these channels such as the recording of graphic images, sounds, picture images, are being considered. A standard for the recording format of graphic image has been already proposed. The MIDI signal can be recorded in this user's bit.
In this case, in addition to the viewing and listening of recorded programs by the supply of audio and video signals reproduced by the disc player to an audio visual (AV) system, it is possible to supply information of programs to be played to one or more MIDI apparatuses provided besides the audio visual system. Therefore, various possibility of the utilization of this arrangement, such as the construction of an AV system including electronic musical instruments and capable of a program reproduction with full of presence, or the application to the production of educational softwares, are being considered.
MIDI apparatuses are configured to perform a music according to a musical instrument playing program which is constituted by the MIDI signal successively supplied from the disc player. Therefore, if the disc player receives a command of an operation requiring a track jump while the player is transmitting the musical instrument playing program, it becomes no more possible to read the program in the order of writing, which results in the generation of a discontinuity in the musical instrument playing program. Consequently, there may arise various inconveniences such as the impossibility to stop the generation of sound from the sound source of the MIDI apparatuses.